can you train yourself to see this change? I think I’m too slow or absent minded to notice this.
The researchers used an infrared eye-tracking device to measure the diameter of the participants’ left pupils up to 2,000 times per second while they performed the tasks. They found that pupil dilation was tightly coupled with the time at which the decisions were made, and betrayed the participants’ decisions before they were openly revealed. In the first experiment, maximum pupil dilation was observed during the 2-second interval in which the button was pressed. In the second, where there was a delay between the choice and the participants’ report of which number they had chosen, their pupils were maximally dilated during the interval at which they chose the digit. During task three, maximum dilation was again observed during the time at which the participants “chose” the underlined number.
via Your eyes betray the timing of your decisions : Neurophilosophy.